• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1763-1770
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• 2023

The availability of high-resolution satellite image time series data has led to an increase in change detection research. Various methods are being studied, such as satellite image pixel and object-level change detection algorithms, as well as algorithms that apply deep learning technology. In this paper, we propose a QGIS plugin-based system to enhance the utilization of these useful results and present an actual implementation case. The proposed system is a system for intensive change detection and monitoring of areas of interest, and we propose a convenient system expansion method for algorithms to be developed in the future. Furthermore, it is expected to contribute to the construction of satellite image utilization systems by presenting the basic structure of commercialization of change detection research.

• Journal of the Korea Society of Computer and Information
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• v.28 no.12
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• pp.221-229
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• 2023

Recently, Grid-forming(GFM) converter, which offers features such as virtual inertia, damping, black start capability, and islanded mode operation in power systems, has gained significant attention. However, in low-voltage microgrids(MG), it faces challenges due to the coupling phenomenon between active and reactive power caused by the low line impedance X/R ratio and a non-negligible power angle. This power coupling issue leads to stability and performance degradation, inaccurate power sharing, and control parameter design problems for GFM converters. Therefore, this paper serves as a review study on not only control methods associated with GFM converters but also power decoupling techniques. The aim is to introduce promising control methods and enhance accessibility to future research activities by providing a critical review of power decoupling methods. Consequently, by facilitating easy access for future researchers to the study of power decoupling methods, this work is expected to contribute to the expansion of distributed power generation.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1073-1080
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• 2023

The development and speed improvement of the Internet network, and the development of many platforms based on it, have brought about a rapid expansion of production and consumption of various contents. However, the existing IP-based Internet system cannot efficiently cope with such an urgent increase in data. Accordingly, an alternative called the CCN(Contents Centric Network) has emerged, enabling more efficient data transmission and reception centered on content rather than host. In this paper, we will deal with the mobility of intermediate nodes in CCN real-time streaming service, which is one of the major research fields of CCN, and minimize network overload through more efficient path switching through RSSI detection. In other words, by improving the method of selecting and switching a spare path when an intermediate node located between the requester(consumer) and the provider moves, a mechanism for managing data transmission is not interrupted and unnecessary load due to route switching does not occur in the network.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.78-84
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• 2023

Recently, the world's countries are tightening regulations on CO2 and air pollutants emission to solve them. In addition, eco friendly vehicles is increasing to replace automobiles in internal combustion engine. The government is supporting the expansion of hydrogen refueling infrastructure according to the hydrogen economy road map. In particular, refueling station is important to secure the safety that supplies high-pressure hydrogen with a wide LFL range. This paper is on guidelines for the determination safety distances to ensure worker safety from accident as jet fire. The safety distance is set according to the procedure of the EIGA doc 075/21. For accident frequency is upper 3.5E-05 per annum, safety distance is decided via consequence analysis where the risk of harm is below individual harm exposure threshold.

• International Journal of Computer Science & Network Security
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• v.24 no.6
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• pp.200-206
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• 2024

Laser induced breakdown spectroscopy (LIBS) technique has been used for the elemental composition of the soils. In this technique, a high energy laser pulse is focused on a sample to produce plasma. From the spectroscopic analysis of such plasma plume, we have determined the different elements present in the soil. This technique is effective and rapid for the qualitative and quantitative analysis of all type of samples. In this work a Q-switched Nd: YAG laser operating with its fundamental mode (1064 nm laser wavelength), 5 nanosecond pulse width, and 10 Hz repetition rate was focused on soil samples using 10 cm quartz lens. The emission spectra of soil consist of Iron (Fe), Calcium (Ca), Titanium (Ti), Silicon (Si), Aluminum (Al), Magnesium (Mg), Manganese (Mn), Potassium (K), Nickel (Ni), Chromium (Cr), Copper (Cu), Mercury (Hg), Barium (Ba), Vanadium (V), Lead (Pb), Nitrogen (N), Scandium (Sc), Hydrogen (H), Strontium (Sr), and Lithium (Li) with different finger-prints of the transition lines. The maximum intensity of the transition lines was observed close to the surface of the sample and it was decreased along the axial direction of the plasma expansion due to the thermalization and the recombination process. We have also determined the plasma parameters such as electron temperature and the electron number density of the plasma using Boltzmann's plot method as well as the Stark broadening of the transition lines respectively. The electron temperature is estimated at 14611 °K, whereas the electron number density i.e. 4.1 × 10¹⁶ cm^-3 lies close to the surface.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.57-65
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• 2024

In a fire-resistant structure, uncertainties arise in factors such as ventilation, material elasticity modulus, yield strength, coefficient of thermal expansion, external forces, and fire location. The ventilation uncertainty affects thefactor contributes to uncertainties in fire temperature, subsequently impacting the structural temperature. These temperatures, combined with material properties, give rise to uncertain structural responses. Given the nonlinear behavior of structures under fire conditions, calculating fire fragility traditionally involves time-consuming Monte Carlo simulations. To address this, recent studies have explored leveraging machine learning algorithms to predict fire fragility, aiming to enhance efficiency while maintaining accuracy. This study focuses on predicting the fire fragility of a steel moment frame building, accounting for uncertainties in fire size, location, and structural material properties. The fragility curve, derived from nonlinear structural behavior under fire, follows a log-normal distribution. The results demonstrate that the proposed method accurately and efficiently predicts fire fragility, showcasing its effectiveness in streamlining the analysis process.

• Journal of the Korean Society of Clothing and Textiles
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• v.48 no.1
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• pp.50-65
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• 2024

By analyzing the style of creator avatars in the world of Metaverse, which is emerging as a fourth-generation social media platform, this study aims to identify the meta-fashion tastes of Generation Z (Gen Z) creators (born in the late 2010s and early 2020s) and to analyze the extent to which current trends in the fashion market are influencing meta-fashion. The research method uses a case study to compare meta-fashion and current fashion trends. First, five Gen Z fashion creators on ZEPETO were selected to analyze the meta-fashion styles presented by this group. In the end, a total of 100 fashion styles were analyzed by combining 50 items each from the current meta-fashion and real fashion trends. The fashion styles were found to be hip-hop, easy-casual, punk, lovely feminine, and sexy, and the main fashion items were analyzed as jeans, hip-hop style pants, sneakers, tight crop tops, dresses, tattoos, chain accessories, and dyeing. Meta-fashion is the emergence of items similar in shape to those popular in the current fashion market, but are more exaggerated or show off the human body than actual fashion items.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.141-151
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• 2023

Recently, due to the expansion of the logistics industry, demand for logistics automation equipment is increasing. The modern logistics industry is a high-tech industry that combines various technologies. In general, as various technologies are grafted, the complexity of the system increases, and the occurrence rate of defects and failures also increases. As such, it is time for a predictive maintenance model specialized for logistics automation equipment. In this paper, in order to secure the operational safety and reliability of the parcel loading system, a predictive maintenance platform was implemented based on the Naive Bayes-LSTM(Long Short Term Memory) model. The predictive maintenance platform presented in this paper works by collecting data and receiving data based on a RabbitMQ, loading data in an InMemory method using a Redis, and managing snapshot DB in real time. Also, in this paper, as a verification of the Naive Bayes-LSTM predictive maintenance platform, the function of measuring the time for data collection/storage/processing and determining outliers/normal values was confirmed. The predictive maintenance platform can contribute to securing reliability and safety by identifying potential failures and defects that may occur in the operation of the parcel loading system in the future.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.55-63
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• 2024

Purpose : The purpose of this study is to determine the effects of scapula and pelvis symmetrical reciprocal pattern exercise of PNF concept on respiratory function and quality of life in elderly subjects. Methods : Nineteen elderly subjects with healthy were recruited. Subjects performed scapula and pelvis symmetrical reciprocal pattern exercise of PNF concept. Exercise was appied 30 minutes three times per week for four weeks. The respiratory function and quality of life (QOL) test three times (before, two weeks, and four weeks). Respiratory function includes forced vital capacity (FVC), forced expiratory volume at one second (FEV₁), Peak Expiratory Flow (PEF) and chest cage expansion test (CCET). The QOL test was measured Korean WHOQOL-BRIEF. The analysis method was analyzed through the one-way ANOVA repeated methods, and the statistical significance is α=.05. It was analyzed through the post test Bonferroni test. Results : After the 4 week scapula and pelvis symmetrical reciprocal pattern exercise of PNF concept showed statistically significant differences in the respiratory function (FVC, FEV₁, PEF, and CCET), and QOL (p<.05). As a result of the post-hoc test, FVC showed a significant increase in the mid test and post test compared to the pre test (p<.05), FEV₁ showed a significant increase in the post test compared to the pre test (p<.05). PEF showed a significant increase in all pre-test, mid-test, and post-test sections (p<.05), CCET showed a significant increase in all pre-test, mid-test, and post-test sections (p<.05). QOL showed a significant increase in all pre-test, mid-test, and post-test sections (p<.05). Conclusion : In this study, the scapula and pelvis symmetrical reciprocal pattern exercise of PNF concept improved respiratory function and QOL. The findings suggest that this intervention could be beneficial in improving respiratory function and QOL in the elderly.

• Journal of Electrochemical Science and Technology
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• v.15 no.2
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• pp.291-298
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• 2024

Due to its high theoretical capacity, Silicon (Si) has shown great potential as an anode material for lithium-ion batteries (LIBs). However, the large volume change of Si during cycling leads to poor cycling stability and low Coulombic efficiency. In this study, we synthesized Si/Carbon C45:Graphene composites using a ball-milling method with a fixed Si content (20%) and investigated the influence of the C45/Gr ratio on the electrochemical performance of the composites. The results showed that carbon C45 networks can provide good conductivity, but tend to break at Si locations, resulting in poor conductivity. However, the addition of graphene helps to reconnect the broken C45 networks, improving the conductivity of the composite. Moreover, the C45 can also act as a protective coating around Si particles, reducing the volume expansion of Si during charging/discharging cycles. The Si/C45:Gr (70:10 wt%) composite exhibits improved electrochemical performance with high capacity (~1660 mAh g^-1 at 0.1 C) and cycling stability (~1370 mAh g^-1 after 100 cycles). This work highlights the effective role of carbon C45 and graphene in Si/C composites for enhancing the performance of Si-based anode materials for LIBs.